The Biostatistics Center of The George Washington University proposes to work in cooperative agreement with the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK-NIH) to serve as the Data Coordinating Center (DCC) for a proposed multi-center clinical trial of the medical therapy of benign prostatic hyperplasia (BPH). the purpose of the NIH-BPH Clinical Trial is to determine the safety and efficacy of the pharmacotherapies finasteride (an inhibitor of 5-alpha-reductase) and doxazosin (a blocker of alpha-1 adrenoreceptors) on the clinical progression of BPH. The objective of the transition phase is to finalize the protocol, operations manual and data collection forms to be implemented in a 6 year full-scale clinical trial. The trial will require randomization of 2,800 participants with a diagnosis of BPH over a 2 year period in 17 clinical centers. Eligible participants will be randomly assigned, double-masked, to one of four treatment groups: (1) active finasteride (5 mg., once per day) and active doxazosin (4 mg or 8 mg, once per day); (2) active finasteride and doxazosin placebo; (3) finasteride placebo and active doxazosin; or (4) finasteride placebo and doxazosin placebo. Randomized participants will be followed for a minimum of 4 years (maximum of 6 years) with quarterly follow-up visits. Clinical progression of BPH is defined by the incidence of acute urinary retention, renal insufficiency, recurrent urinary tract infections, incontinence, or a pre-specified increase in the American Urological Association (AUA) symptom score. Secondary outcomes include differences over time among the four treatment groups with respect to AUA symptom score Quality of Life and maximal uroflow. Tissue biopsies will be obtained in 20 percent of the participants to provide information on the histopathobiology of BPH and to test existing biomarkers for their prognostic ability regarding response to medical therapy. The specific aims of the DCC are to provide centralized support and biostatistical consultation in the transition of the pilot study's patient management protocols, operations manual, data collection forms and randomization procedures to the full-scale clinical trial; implementation of a data processing system including data quality assessment; interim analysis of protocol performance, patient safety and treatment efficacy; ad final analysis for publication of the NIH-BPH Clinical Trial results in collaboration with the clinical investigators.